Rib structure for shock absorption, molded pulp cushioning material, packaging material, and packaging system

Abstract

To provide a rib structure for impact buffering of a pulp mold buffering material which can reduce impact acceleration applied on a packaging object more than that with conventional specifications.SOLUTION: A rib structure for impact buffering of a pulp mold buffering material according to the present invention is a hollow rib structure for impact buffering which comprises a top plate and a side wall, with a bottom portion being open. In the rib structure for impact buffering, at least one opening part is provided in a range equal to or less than a half of height of the side wall, with a distance from the bottom portion to the top plate defined to be height of the rib structure for impact buffering. This configuration makes rigidity of an upper part and rigidity of a lower part of the rib structure almost the same, so as to be compatible, so that the entire rib structure can be uniformly compressed and / or collapsed.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a shock absorbing rib structure, a molded pulp cushioning material, a packaging material, and a packaging system. [Background technology]

[0002] Toward the realization of a recycling-oriented society, the reduction of the use of single-use plastics has been included in the environmental management policies of various companies. In addition, in order to deal with recent environmental issues such as marine plastic waste, there is a demand to reduce the use of plastic packaging materials. As a result, the value of pulp molded packaging materials, which are highly recoverable and recyclable, is increasing even further.

[0003] Molded pulp cushioning can absorb the shock, i.e., the shock acceleration, that is applied to the packaged object due to vibration or dropping impact during the logistics process, through its own deformation and buckling action. For example, even if the packaged object is subjected to a shock acceleration of up to several hundred G, there is a known technology that can reduce the shock acceleration to less than 100 G by using cushioning material, and this technology is already being implemented.

[0004] The conventional pulp molded cushioning material 100 shown in FIG. 1 has an accommodation space 105 for the packaged item and is basically configured with a cylindrical or rectangular shock-absorbing rib structure 110 that provides shock-absorbing functionality.

[0005] Furthermore, for example, Patent Document 1 discloses a configuration in which a slit is provided in the portion of a pulp molded cushioning material that receives an item to be packaged, and the portion is compressed to conform to the shape of the item to be packaged, thereby forming an area to accommodate the item to be packaged. Summary of the Invention [Problem to be solved by the invention]

[0006] Packaging materials for precision instruments that use pulp molded cushioning materials do not have very high impact resistance, and there is a risk of the packaged object being damaged. Therefore, pulp molded cushioning materials are required to have the function of reducing impact acceleration. However, there is a problem in that the impact cushioning rib structure of the pulp molded cushioning material described above has reached its limit in reducing impact acceleration.

[0007] Therefore, an object of the present invention is to provide an impact absorbing rib structure for a pulp molded cushioning material that can reduce impact acceleration more than conventional specifications. [Means for solving the problem]

[0008] The above problem is solved by a shock absorbing rib structure for a pulp molded shock absorbing material, which is a hollow shock absorbing rib structure consisting of a top plate and a side wall and having an open bottom surface, and at least one opening is provided within a range of the side wall that is equal to or less than half the height of the shock absorbing rib structure, with the distance from the bottom surface to the top plate being the height of the shock absorbing rib structure. The side wall has a gradient in a height direction, and the width of the opening is approximately 2a, where a is a distance perpendicular to the height direction from a center position of the height of the side wall to an end of the bottom side of the opening in a cross section of the height direction of the shock absorbing rib structure and on the outer surface of the side wall. The above-mentioned problem is solved by a shock absorbing rib structure. Effect of the Invention

[0009] The shock absorbing rib structure of the present invention has at least one opening in a range of less than half the height of the side wall. This makes the rigidity of the upper and lower parts of the rib structure approximately equal, and provides consistency, allowing the entire rib structure to be uniformly compressed and / or crushed. By using the overall height of the rib structure as a shock absorbing mechanism, the spring constant of the entire rib structure can be reduced, and the shock acceleration applied to the packaged item can be reduced compared to conventional specifications. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a conventional pulp molded cushioning material. [Diagram 2] FIG. 1 is a perspective view of a shock absorbing rib structure according to a conventional specification. [Diagram 3] FIG. 11 is a schematic cross-sectional view showing compressive deformation of a side wall in a conventional specification. [Figure 4] 1 is a graph showing the impact coefficient of a cushioning material. [Diagram 5] FIG. 11 is a schematic cross-sectional view showing an example of a clearance that prevents a packaged object from hitting the bottom. [Figure 6] FIG. 2 is a schematic cross-sectional view showing a sloped sidewall of the shock absorbing rib structure. [Figure 7] FIG. 2 is a schematic cross-sectional view showing a sidewall with a varying perimeter (cross-sectional area). [Figure 8] 1 is a perspective view of a shock absorbing rib structure according to a first embodiment of the present invention; [Figure 9] 5A to 5C are schematic cross-sectional views showing deformations of the impact-absorbing rib structure in the first embodiment. [Figure 10] FIG. 4 is a schematic diagram showing dimensions of an opening provided in a side wall. [Figure 11] FIG. 6 is a perspective view of a shock absorbing rib structure according to a second embodiment of the present invention. [Figure 12] 10A to 10C are schematic cross-sectional views showing deformations of the impact-absorbing rib structure in the second embodiment. [Figure 13] FIG. 11 is a perspective view of an impact-absorbing rib structure according to a third embodiment of the present invention. [Figure 14] 13A to 13C are schematic cross-sectional views showing deformations of the impact-absorbing rib structure in the third embodiment. [Figure 15] FIG. 2 is a schematic diagram showing a circular opening provided in a side wall. [Figure 16] 1 is a perspective view showing a pulp molded cushioning material provided with an impact cushioning rib structure of the present invention; [Figure 17] FIG. 1 is a schematic diagram showing the test format in verification test No. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Before describing the embodiments, some preliminary points will be described below to facilitate understanding of the embodiments.

[0012] 2, a conventional shock absorbing rib structure 110 is made up of a top plate 12 and side walls 14, and has a hollow structure with an open bottom surface 16, that is, (a) a rectangular column or (b) a cylindrical column structure. The shock absorbing mechanism of this shock absorbing rib structure 110 is as follows.

[0013] 3A and 3B are schematic cross-sectional views showing the compressive deformation of the side wall in the conventional specification. As shown in FIG. 3A, the shock absorbing rib structure 110 is seen in the direction of the arrow A in FIG.

[0014] With respect to the dynamic load DL received from the packaged object 20 when dropped as packaged cargo, the impact absorbing rib structure 110 mainly supports the dynamic load DL with the side walls 14, and absorbs the impact with the compressive or crushing stress caused by the compressive deformation of the side walls 14. In other words, the compressive deformation of the side walls 14 of the impact absorbing rib structure 110 reduces the impact acceleration applied to the packaged object 20, thereby protecting the packaged object 20.

[0015] The design of such a shock absorbing rib structure uses the basic formula shown in the following formula (1). G (impact acceleration) = C (impact coefficient) × h (drop height) / t (thickness of cushioning material) (1)

[0016] Specifically, we aim for the strain (ε) that minimizes the impact coefficient (C) determined by the stress characteristics of the cushioning material (see Figure 4), and also consider that the packaged object does not hit the bottom inside the packaged cargo. For example, as shown in Figure 5, the clearance t c Then, the support area of ​​the cushioning material that supports the weight of the packaged item is adjusted so that the instantaneous distortion of the shock absorbing rib structure is usually designed to be within the range of 0.4 to 0.6.

[0017] However, with the conventional shock-absorbing rib structure 110 shown in FIG. 2 and the above-mentioned design method, the impact acceleration (G) has reached its reduction limit, and in order to further improve the shock-absorbing performance, a new shock-absorbing rib structure with a lower impact coefficient (C) is required.

[0018] In response to this, the present inventors closely observed the deformation state of the conventional shock absorbing rib structure 110 and noticed that compression and crushing occurred biased toward the top plate 12 side (see FIG. 3). In other words, they found that the entire height of the rib structure was not being utilized, and the potential spring constant of the entire rib structure was being lost.

[0019] Fig. 6 is a schematic cross-sectional view showing a side wall having a gradient. As shown in Fig. 6(a), the shock-absorbing rib structure 110 is seen in the direction of arrow A in Fig. 6(b). The side wall 14 of the shock-absorbing rib structure 110 has a gradient (Δθ) due to its molding. This gradient is provided in advance in the product shape to make it easier to remove the molded product from the mold.

[0020] 7 is a cross-sectional view showing a sidewall whose perimeter (cross-sectional area) changes. Cross sections B and C show the shock-absorbing rib structure 110 as viewed in the directions of arrows B and C, respectively. Since the shock-absorbing rib structure 110 has a gradient (Δθ), the perimeter (cross-sectional area) of the sidewall 14 gradually increases toward its bottom surface 16 (opening bottom surface 16).

[0021] Therefore, the stress due to compression or crushing gradually decreases toward the lower portion (bottom surface 16) of the rib structure 110. Therefore, it is considered that the compression or crushing occurs unevenly on the top plate 12 side, which has a relatively weak structure.

[0022] In the following embodiment, a shock absorbing rib structure for a pulp molded cushioning material that can reduce the impact acceleration more than conventional specifications will be described.

[0023] (First embodiment) Fig. 8 is a perspective view of the shock absorbing rib structure according to the first embodiment of the present invention. As shown in Fig. 8, the shock absorbing rib structure 10, 10' of this embodiment is composed of a top plate 12 and a side wall 14, and has a hollow structure with an open bottom surface 16, that is, (a) a rectangular column structure or (b) a cylindrical column structure. The distance from the bottom surface 16 to the top plate 12 is defined as the height h of the shock absorbing rib structure, and a plurality of openings 18 are provided within a range of less than half the height h of the side wall 14.

[0024] The shock-absorbing rib structures 10, 10' reduce the rigidity of the lower part of the rib structure by providing openings 18 in the lower part (a range equal to or less than half the height h) of the side walls 14. In other words, by making the rigidity of the upper and lower parts of the rib structure approximately the same and providing consistency, the entire rib structure can be uniformly compressed and / or crushed.

[0025] Fig. 9 is a schematic cross-sectional view showing a modification of the shock-absorbing rib structure in this embodiment. As shown in Fig. 9(a), the shock-absorbing rib structure 10 is viewed in the direction of arrow A in Fig. 9(b).

[0026] The impact-absorbing rib structure 10 supports the dynamic load DL from the packaged item 20 mainly with the side walls 14, but differs from the conventional specification (see FIG. 3) in that the side walls 14 are compressed and crushed over their entire range in the height direction.

[0027] In this way, by using the overall height of the rib structure as an impact cushioning mechanism, the spring constant can be reduced compared to conventional specifications, reducing the impact acceleration applied to the packaged item.

[0028] (Opening width) Fig. 10 is a schematic diagram showing the dimensions of an opening provided in a side wall. As shown in Fig. 10(a), the side wall 14 has a gradient in the height direction. On the outer surface of the side wall 14, the distance perpendicular to the height direction from the center position (h / 2) of the height of the side wall 14 to the edge of the bottom surface 16 of the opening 18 is defined as a.

[0029] 10(b), it is most desirable to set the width W of the opening 18 to approximately 2a (W≈2a) in order to make the rigidity of the upper and lower parts of the rib structure equal. The verification results for this will be described later.

[0030] Second embodiment Fig. 11 is a perspective view of a shock absorbing rib structure according to a second embodiment of the present invention. In Fig. 11, the same components as those in Fig. 8 are given the same reference numerals and detailed description thereof will be omitted.

[0031] As shown in FIG. 11, the impact cushioning rib structure 10a of the pulp molded cushioning material differs from the impact cushioning rib structure 10 of the first embodiment in that multiple openings 18a are provided near the center of the height of the side wall 14.

[0032] This is intended to cause bending at the center by providing a weakened portion near the center of the height of the side wall 14.

[0033] Fig. 12 is a schematic cross-sectional view showing a modification of the shock-absorbing rib structure in this embodiment. As shown in Fig. 12(a), the shock-absorbing rib structure 10a is seen in the direction of arrow A in Fig. 12(b).

[0034] The impact buffering rib structure 10 supports the dynamic load DL from the packaged object 20 mainly by the side wall 14, but differs from the previous embodiment in that bending / buckling occurs in the side wall 14. By generating a bending stress smaller than the compressive stress over the entire area of ​​the side wall 14, the impact acceleration acting on the packaged object 20 can be reduced.

[0035] Third embodiment Fig. 13 is a perspective view of a shock absorbing rib structure according to a third embodiment of the present invention. In Fig. 13, the same components as those in Fig. 8 are given the same reference numerals and detailed description thereof will be omitted.

[0036] As shown in FIG. 13, the impact cushioning rib structure 10b of the pulp molded cushioning material differs from the impact cushioning rib structures of the first and second embodiments in that multiple openings 18b are provided over an area of ​​more than half the height of the side wall 14.

[0037] The intention is to provide a weakened portion at the top of the sidewall 14 so that the upper portion of the rib structure will buckle early due to the low stress caused by bending stress, and then compress and / or collapse below the center of the rib structure.

[0038] Fig. 14 is a schematic cross-sectional view showing a modification of the shock-absorbing rib structure in this embodiment. As shown in Fig. 14(a), the shock-absorbing rib structure 10b is seen in the direction of arrow A in Fig. 14(b).

[0039] The impact-absorbing rib structure 10 supports the dynamic load DL from the packaged item 20 mainly through the side walls 14, but bending and buckling occurs in the upper part of the side walls 14, and compression and crushing occurs in the central part and below.

[0040] The impact-absorbing rib structure 10b of this embodiment reduces the stress acting from the upper part of the rib structure at the beginning of the impact occurrence, thereby preventing the packaged object from being subjected to a sudden impact and reducing the acceleration occurring in the internal components of the packaged object.

[0041] Subsequently, advantageous configurations of the invention will be explained.

[0042] (Opening arrangement) Openings 18, 18a, 18b (hereinafter, only 18 will be referred to) may be provided at only one location in side wall 14 of the shock absorbing rib structure. Furthermore, when multiple openings 18 are provided, it is preferable to arrange them at equal intervals in the width direction of the side wall. This allows the shock absorbing rib structure to have uniform rigidity all around, providing an even greater effect.

[0043] (Shape of opening) The shape of the opening is preferably polygonal (FIG. 8) or circular (FIG. 15). Impacts do not necessarily act on the shock-absorbing rib structure in a vertical direction, but may also act from unintended directions. By making the shape of the opening 18 polygonal or circular, it is possible to accommodate impacts from various directions.

[0044] (Shape of shock absorbing rib structure) The shock absorbing rib structure is preferably a square pillar or a cylinder, as shown in Fig. 8. As explained in (Shape of opening), it can handle shocks from various directions. In particular, if the shock absorbing rib structure is a square pillar, it has excellent moldability and can improve productivity.

[0045] 16 is a perspective view showing a pulp-molded cushioning material provided with the shock-absorbing rib structure of the present invention. This pulp-molded cushioning material 30 is provided with at least one of the shock-absorbing rib structures 10 of the first to third embodiments. This pulp-molded cushioning material 30 can accommodate a packaged object and reduce the impact acceleration applied to the packaged object more than conventional pulp-molded cushioning materials.

[0046] It is desirable that the top plate of the shock absorbing rib structure 10 abuts against the packaged object. By supporting the packaged object at the intended position, the packaged object can be stably stored and held.

[0047] It is also desirable that the open bottom surface 16 (see, for example, FIG. 8) of the shock-absorbing rib structure 10 abuts against the packaged object. The product storage surface 40 of the pulp molded cushioning material 30 abuts against the flat surface of the packaged object, thereby enabling stable storage and holding.

[0048] The pulp molded cushioning material 30 of this embodiment is attached to an image forming device (e.g., a copier, a printer, etc.) as a packaged object, and is then packaged in a packaging material (e.g., a cardboard box). This packaging material is used in a packaging system that includes packaging machinery and equipment.

[0049] (Verification test 1) A comparative verification test of response acceleration of packaged objects using the shock absorbing rib structure of the conventional specification and the shock absorbing rib structure of the present invention will be described. Verification method: A drop test was conducted under the following conditions for the conventional shock-absorbing rib structure and the shock-absorbing rib structure of the present invention, and the impact acceleration applied to the packaged item was measured.

[0050] Test specimen (see Figure 17): Main component m1 (aluminum material with a mass of 1.02 kg) Internal part m2 (aluminum material with mass 0.2 kg) Intermediate member k1 (gel sheet with a mass of 0.01 kg) Cushioning material k2 (cardboard waste paper pulp mold cushioning material thickness t=3mm) Here, the main member m1 is a model of the entire copier (an example of precision machinery), the internal part m2 is a model of a part built into the copier, and the intermediate member k1 is a model of a part that supports the internal part m2 on the main member m1, and acts as a spring element. The support relationship between the internal part m2 and the intermediate member k1 was set to have a natural frequency of 200 Hz.

[0051] Cushioning material type: Sample 1: Pulp molded cushioning material with a conventional shock absorbing rib structure (Figure 2(a)) Sample 2: A pulp molded cushioning material having the shock absorbing rib structure of the first embodiment (a square pillar having four openings at the bottom, FIG. 8(a)). Sample 3: A pulp molded cushioning material having a shock absorbing rib structure according to the second embodiment (a square pillar having four openings in the center, FIG. 11). Sample 4: Pulp molded cushioning material having a shock absorbing rib structure according to the third embodiment (a square pillar having four openings at the top, FIG. 13).

[0052] Conditions and Evaluation Criteria: It is allowed to fall freely from a height of 80 cm onto a flat floor. For samples 1 and 4, the impact acceleration applied to the main member m1 and the internal part m2, respectively, was measured. For samples 2 and 3, the impact acceleration applied to the main member m1 is measured.

[0053] Results: The results are shown in Table 1. Compared to sample 1 (conventional specification), samples 2 and 3 (first and second embodiments) showed a reduced impact acceleration on the main member m1. Also, compared to sample 1 (conventional specification), sample 4 (third embodiment) showed a reduced impact acceleration on the internal part m2.

[0054] [Table 1]

[0055] (Verification test 2) Comparative verification test of shock absorption according to opening width Verification method: In a pulp molded cushioning material having the impact-absorbing rib structure of the first embodiment (a rectangular column with four openings at the bottom, FIG. 8(a)), the width of the openings was changed to two types, and the impact acceleration applied to the packaged item was measured.

[0056] Sample: Main component m1 (aluminum material with a mass of 1.02 kg) Cushioning material k2 (cardboard waste paper pulp mold cushioning material thickness t=3mm)

[0057] Cushioning material type: Sample 5: A pulp molded cushioning material having the shock absorbing rib structure of the first embodiment (a square pillar having four openings at the bottom, FIG. 8(a)). Here, the width W of the opening 18 shown in FIG. 10 is set to a (W≈a). Sample 6: A pulp molded cushioning material having the shock absorbing rib structure of the first embodiment (a square pillar having four openings at the bottom, FIG. 8(a)). Here, the width W of the opening 18 shown in FIG. 10 is set to 2a (W≈2a).

[0058] Conditions and Evaluation Criteria: It is allowed to fall freely from a height of 80 cm onto a flat floor. For both samples 5 and 6, the impact acceleration applied to the main member m1 is measured.

[0059] Results: The results are shown in Table 2. The results showed that the impact acceleration was lower in sample 6 (width W of opening 18 ≈ 2a) than in sample 5 (width W of opening 18 ≈ a).

[0060] [Table 2]

[0061] These verification tests show that the configurations of the various embodiments of the present invention can reduce the impact acceleration applied to the packaged object (and internal parts) compared to configurations of conventional specifications.

[0062] The present invention has been described in detail above using the embodiments. The embodiments are merely examples, and various modifications can be made without departing from the scope of the present invention. For example, a plurality of embodiments and advantageous configurations may be combined. [Explanation of symbols]

[0063] 5, 105 Storage space 10, 10', 10a, 10b, 110 Shock absorbing rib structure 12 Tabletop 14 Side wall 16 (Opening) Bottom 18, 18a, 18b: opening 20 Packaged object 30, 100: Molded pulp cushioning material 40 Product storage surface [Prior art documents] [Patent documents]

[0064] [Patent Document 1] JP 2006-89074 A

Claims

1. A shock absorbing rib structure for a pulp molded cushioning material, comprising: A hollow shock absorbing rib structure consisting of a top plate and side walls and an open bottom, The distance from the bottom surface to the top plate is defined as the height of the shock absorbing rib structure, At least one opening is provided in a range of the side wall not exceeding half of the height, The side wall has a slope in a height direction, At a cross section in the height direction of the impact absorbing rib structure and at an outer surface of the side wall, The distance perpendicular to the height direction from the center position of the height of the side wall to the end of the bottom surface side of the opening is defined as a, A shock absorbing rib structure, characterized in that the width of the opening is approximately 2a.

2. 2. The shock absorbing rib structure according to claim 1, wherein the openings are arranged at equal intervals in a width direction of the side wall.

3. 3. The shock absorbing rib structure according to claim 1, wherein the opening has a polygonal or circular shape.

4. 4. The shock absorbing rib structure according to claim 1, wherein the shock absorbing rib structure is a rectangular column or a cylindrical column.

5. 5. The shock absorbing rib structure according to claim 1, wherein the shock absorbing rib structure is a quadrangular prism.

6. The container has a storage space for an object to be packaged, A pulp molded cushioning material provided with at least one impact cushioning rib structure according to any one of claims 1 to 5.

7. 7. The pulp molded cushioning material according to claim 6, wherein the top plate of the shock absorbing rib structure abuts against the packaged object.

8. 7. The pulp molded cushioning material according to claim 6, wherein the open bottom surface of the shock absorbing rib structure abuts against the packaged object.

9. A packaging material for packaging a packaged object equipped with the pulp molded cushioning material described in any one of claims 6 to 8.

10. A packaging system using the packaging material described in claim 9.

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